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Harvard Forest Data Archive


CFCs and Radiatively Important Trace Species at Harvard Forest EMS Tower 1996-2005

Related Publications



  • Lead: Steven Wofsy, Elaine Gottlieb
  • Investigators: Diana Barnes, Geoff Dutton, James Elkins, Michael McElroy
  • Contact: Information Manager
  • Start date: 1996
  • End date: 2005
  • Status: completed
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.537755
  • Longitude: -72.171478
  • Elevation: 340 meter
  • Taxa:
  • Release date: 2009
  • Revisions:
  • EML file: knb-lter-hfr.67.21
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: long-term measurement
  • Research topic: forest-atmosphere exchange
  • LTER core area: inorganic nutrients
  • Keywords: air pollution, carbon monoxide, hydrogen, nitrous oxide, sulfur hexafluoride, urban
  • Abstract:

    Measurements of 13 ozone-depleting and/or greenhouse gases are taken above the forest canopy at Harvard Forest, downwind of the New York City - Washington, D. C. corridor, every 25 minutes using a four-channel gas chromatographic system called FACTS (Forest and Atmosphere Chromatograph of Trace Species). The species measured are H2, CO, CH4, methyl chloroform (CH3CCl3), chloroform (CHCl3), carbon tetrachloride (CCl4), CFC-11 (CCl3F), CFC-12 (CCl2F2), CFC-113 (C2Cl3F3), halon-1211 (CBrClF2), perchlorethylene (C2Cl4), nitrous oxide (N2O), and sulfur hexafluoride (SF6). Observations began in January 1996 and are continuing.

  • Methods:

    FACTS is a fully automated, four-channel gas chromatograph with packed columns and electron capture detectors. Atmospheric measurements alternate with calibration standard measurements every 25 minutes; the air samples are from above the canopy of the forest (29 m).

  • Use:

    This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.

  • Citation:

    Wofsy S, Gottlieb E. 2009. CFCs and Radiatively Important Trace Species at Harvard Forest EMS Tower 1996-2005. Harvard Forest Data Archive: HF067 (v.21). Environmental Data Initiative:

Detailed Metadata

hf067-01: FACTS data

  1. datetime: date and time
  2. year: year
  3. julian: day number from 1 January 1996 (GMT) (unit: nominalDay )
  4. doy: day of year (GMT) (unit: nominalDay )
  5. wdir: wind direction sector
    • 1: NE (0-90)
    • 2: SE (90-180)
    • 3: SW (180-270)
    • 4: NW (270-360)
  6. h2: Hydrogen (ppb) (unit: dimensionless / missing value: NA)
  7. ch4: Methane (ppb) (unit: dimensionless / missing value: NA)
  8. co: Carbon Monoxide (ppb) (unit: dimensionless / missing value: NA)
  9. cfc12: CFC-12 (ppb) (unit: dimensionless / missing value: NA)
  10. h1211: Halon 1211 (ppt) (unit: dimensionless / missing value: NA)
  11. cfc11: CFC-11 (ppt) (unit: dimensionless / missing value: NA)
  12. cfc113: CFC-113 (ppt) (unit: dimensionless / missing value: NA)
  13. chcl3: Chloroform (ppt) (unit: dimensionless / missing value: NA)
  14. mc: Methyl Chloroform (CH3CCl3) (ppt) (unit: dimensionless / missing value: NA)
  15. ct: Carbon Tetrachloride (CCl4) (ppt) (unit: dimensionless / missing value: NA)
  16. tce: Trichloroethylene (C2HCl3) (ppt) (unit: dimensionless / missing value: NA)
  17. pce: Perchloroethylene (C2Cl4) (ppt) (unit: dimensionless / missing value: NA)
  18. n2o: Nitrous Oxide (ppb) (unit: dimensionless / missing value: NA)
  19. sf6: SF6 (ppt) (unit: dimensionless / missing value: NA)